I travelled to the United Kingdom to help with fieldwork coordinated by Dave Lowry’s research group at Royal Holloway University of London (RHUL) in November 2017. This trip was part of a knowledge exchange between our lab and Dave Lowry (with whom our lab has previously partnered) that involved a member of each respective group joining each other’s methane measurement campaigns. We completed two days of extensive mobile measurement surveys in several different areas of the UK, all of which offered more varied scenery than that of my most recent Canadian fieldwork in Lloydminster, AB (a plus)!
Day one was spent sampling in a coal mine and around several landfills in Wales. Collected data was used for a student’s senior project, and we were able to have full site-access to the open cut anthracite mine. While at the mine, we drove down in the pit in a Land Rover to continuously measure methane using a portable LGR analyzer. We also periodically took bag samples in areas of high methane concentrations for isotopic analysis, which was done back in Lowry’s lab after the campaigns. The pit is 150 – 200 metres deep and the coal seams, which we were able to see up close, range from a few centimetres to over a metre in thickness. The mine plans to close in 2018, with remediation immediately following. The rest of the day involved scoping out smelly landfills, which was not quite as exciting as touring around a mine in a Land Rover, but still interesting none the less.
Day two consisted of continuous measurement surveys along the North Sea coast, where our main target was large onshore natural gas terminals and compressor stations. We did not have site access to these facilities, so we measured around the perimeters of them and tried to get downwind of any observed plumes.We also took several bag samples during these surveys for isotopic analysis, which made the space in the car very limited by the end of the day!
The next two days were spent in the lab back at RHUL analyzing the bag samples that were collected atsites of interest. Lowry’s lab was equipped with a high-precision, automated mass spectrometer, which was really cool to see in action. While waiting for samples to run, I also explored around the university, which was the most beautiful campus I have ever seen (sorry StFX)!
During this trip, I also represented the Flux Lab at the Industrial Methane Measurement Conference (IMMC), which was held in Antwerp, Belgium. The 2-day conference consisted of several interesting presentations on current methane measurement technologies and challenges in Europe and abroad.
This trip was my first time outside North America, and I was able to take in 3 countries in a short time; I think it goes without saying that this was a field experience I will never forget!
Many thanks to Dave Risk and Dave Lowry for the amazing opportunity.
Wind measurements are an important part of gas leak plume detection, which we do by truck. I’ve been working with ANSYS Fluent software and anemometer measurements from the mobile survey trucks to investigate vehicle-based wind measurements. My MSc. project is a field- simulation study comparing experimental field measurements with CFD simulations, to explain how anemometer placement and the vehicle’s external flow field,affect measurement accuracy of vehicle-mounted anemometers.
Along with Nayani Jensen, I conducted field tests in Saskatchewan to explore the effects of anemometer placement, vehicle speed, and wind yaw angle on measured wind speed and direction. We tested five different anemometer positions on the truck, and used stationary anemometers to compare against the mobile measurements.
We found that our truck-mounted anemometer over-estimated wind speeds, particularly for low mounting positions, high vehicle speeds, and large side winds (> 40% of vehicle speed). This indicated that corrections are needed for vehicle speed and wind yaw angle.
Back at the lab, we used a Toyota Tacoma CAD model to create Computational Fluid Dynamic (CFD) simulations using ANSYS Fluent, to study the flow field around our truck as a function of speed, yaw angle, and anemometer placements. We replicated the conditions under which field tests were conducted, but ANSYS Fluent also allowed us to explore a much wider range of conditions.
Our simulations agreed very closely with field measurements. We are working with the results from the CFD, and field components of this study, to improve our truck-based wind measurements by calibrating anemometer measurements for anemometer placement, vehicle speed, and wind yaw angle.
Measuring wind from trucks isn’t much different than measuring wind from bikes (see this blog post) or from other vessels in motion like boats. Modeling wind fields with CFD has proven a good substitute for field work in these applications.
The rock room has been a space of design and construction for many CO2 soil profilers for arctic field sites, and this summer was no exception. Jack and I created an automated soil gas sampler, for the measurement of methane and CO2 from a series of soil depth chambers in northern Norway. The system included a one-metre long, encased, open path methane analyzer that consecutively received samples from the soil depth chambers. The methane analyzer was not at our disposal during system construction, so a surrogate analyzer was created in the lab using a sealed compost bin equipped with a CO2 probe to mimic the 9L analyzer. It proved to be a great addition to the lab!
Late June Jack and I departed on a three-week journey to the Arctic. The first leg of our trip took us through Iceland to Bergen, where we had four days to work with the methane analyzer and get accustomed to the short nights before experiencing the midnight sun at 69oN. Then the whole team flew to Finnmark, the northernmost county of mainland Norway. We landed in Alta and drove a scenic three hours inland to the small town of Karasjok; the town campground was home base during our stay.
The field site is located at a mire near Iskoras, a 30 minute drive from town and a 3 km walk from the road. The site was selected for its spatial representation of the stages of permafrost degradation. There are four transects throughout the mire, each with four subsites equipped with soil chambers at depth, temperature and moisture sensors, and open top chambers.
During the July visit, another team installed an eddy covariance tower that stayed for the duration of the summer. During the July visit, another team installed an eddy covariance tower that stayed for the duration of the summer. It was a busy, challenging and enjoyable 10 days in the field that entailed many hours armpit-deep in wet soil installing chambers and created an appreciation of the midnight sun’s convenience. We enjoyed frequent chocolate breaks, unique lunches like pickled mackerel on rye, and brown cheese. Quickly, we learned not to stand too still or the mosquitoes would have a feast!
When I returned in September the berries were plentiful, the midnight sun no longer shone, and the flies were still hungry. More soil chambers were installed; 48 depth chambers were spread throughout the four transects and six surface FD chambers, relocated from Svalbard, were installed at the automatic transect. The last day in the field was spent collecting gas samples, and prepping the equipment and site for the fast approaching winter.
Many thanks to Dr. Hanna Lee, Dr. Casper Christiansen and Dr. Dave Risk for their guidance, expertise, and providing the opportunity to expand my field and technical experience throughout the development of this project.
By Renee McDonald